A question about the address of FlashSize

[TinyHai]

First, my mcu is STM32F030F4P6 which has 20 pins.

My project need to store some data in internal flash memory, and I find the program always blocking on FLASH.len().

After I change the code to:

/// Size of integrated flash
#[derive(Debug)]
#[repr(C)]
pub struct FlashSize(u16);
#[cfg(not(any(feature = "stm32f070")))]
define_ptr_type!(FlashSize, 0x1FFF_F7CC);
#[cfg(any(feature = "stm32f070"))]
define_ptr_type!(FlashSize, 0x1FFF_0000);

The program works well.

Is this a bug, or my mcu is fake?